This invention relates in general to automatic timers for electrical appliances and in particular to timers associated with electrical toasters for bread slices or the like.
Timer mechanism for electrical toaster are, of course, well known. Generally, a darkness selecting adjustment device is associated with the toaster appliance usually operative through the timer mechanism to select the duration of the on-time interval for the toaster heater element designed to impart a desired toasting darkness or color to the bread slice being toasted. However, with successive use of the toaster, its temperature status at the beginning of any timed toasting cycle will vary between room temperature and a maximum heat saturation temperature. Such variation will depend on the duration of the preceding off-time interval. Accordingly, toasting darkness selection made through the timer adjustment device often is not reliable. When the darkness selector is initially adjusted, the toaster is cooled to room temperature so that a predetermined transfer of heat occurs during an operational cycle to produce a desired toasting color. If the toaster is operated again following a short off-time interval, it is still quite hot so that the heat transferred is greater for the same duty cycle duration resulting in a darker toasting color. The degree to which the darkness varies from the initial selection depends on the indeterminate duration of the off-time intervals between successive toaster operations and often necessitates changing the setting of the darkness selector and discarding undesirable toasted items.
Various solutions to the foregoing problem come to mind including the provision of automatic heater temperature and timer controls. Generally, such solutions are costly, unreliable and not economically feasible. It is therefore an important object of the present invention to provide a more reliable and economically feasible method and means for minimizing changes in the performance of electrical appliances such as toasters arising because of variations in off-time intervals between successive operations.